The 25-year-old had been linked with a January move to Leicester but that deal fell through, while he was also offered a new contract at Doncaster.

Sharp, who has scored 10 goals in 20 appearances this season, was signed from Sheffield United in July 2010.

The ex-Scunthorpe striker, reunited with old Iron boss Nigel Adkins, moves on a three-and-a-half-year deal.

"It's a massive club with huge ambitions, and that is the main reason I moved," said Sharp. "The gaffer and his coaching team was another reason and it felt right in my head too. I can't wait to get on with the challenge.

"I'm delighted. It has been a long time coming, but I am delighted to get it done, and now I am just looking forward to getting on the pitch and showing the fans what I can do.

I am delighted that I am here and joining a really big club with a strong squad of players, hopefully I can be a cog in the team that helps get this huge club into the Premier League

Billy Sharp

"I got on well with the fans at Doncaster and had an amazing time there and I'm gutted that I had to leave.

"That said, I am delighted that I am here and joining a really big club with a strong squad of players. Hopefully I can be a cog in the team that helps get this huge club into the Premier League."